AUTHOR=Fu Jiafang , Zhong Chuanqing , Zhang Peipei , Zong Gongli , Liu Meng , Cao Guangxiang 

TITLE=Novel Mobilizable Genomic Island GEI-D18A Mediates Conjugational Transfer of Antibiotic Resistance Genes in the Multidrug-Resistant Strain Rheinheimera sp. D18

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.00627

DOI=10.3389/fmicb.2020.00627

ISSN=1664-302X

ABSTRACT=<p>Aquatic environments act as reservoirs of antimicrobial-resistant bacteria and antimicrobial resistance (AMR) genes, and the dissemination of antibiotic resistance from these environments is of increasing concern. In this study, a multidrug-resistant bacterial strain, identified as <italic>Rheinheimera</italic> sp. D18, was isolated from the sea water of an industrial maricultural system in the Yellow Sea, China. Whole-genome sequencing of D18 revealed the presence of a novel 25.8 kb antibiotic resistance island, designated GEI-D18A, which carries several antibiotic resistance genes (ARGs), including <italic>aadA1</italic>, <italic>aacA3</italic>, <italic>tetR</italic>, <italic>tet</italic>(B), <italic>catA</italic>, <italic>dfrA37</italic>, and three <italic>sul1</italic> genes. Besides, integrase, transposase, resolvase, and recombinase encoding genes were also identified in GEI-D18A. The transferability of GEI-D18A was confirmed by mating experiments between <italic>Rheinheimera</italic> sp. D18 and <italic>Escherichia coli</italic> 25DN, and efflux pump inhibitor assays also suggested that <italic>tet</italic>(B) in GEI-D18A was responsible for tetracycline resistance in both D18 and the transconjugant. This study represents the first characterization of a mobilizable antibiotic resistance island in a species of <italic>Rheinheimera</italic> and provides evidence that <italic>Rheinheimera</italic> spp. could be important reservoirs and vehicles for ARGs in the Yellow Sea area.</p>